Project description:The bacterium Aeromonas veronii is a co-pathogenic species that can negatively impact the health of both humans and aquatic animals. In this study, we used single-cell transcriptome analysis (scRNA-seq) to investigate the effects of infection with A. veronii on head kidney cells and the regulation of gene expression in the dark sleeper (Odontobutis potamophila). scRNA-seq was used to assess the effects of infection with A. veronii in O. potamophila B cells, endothelial cells, macrophages, and granulocytes, and differential enrichment analysis of gene expression in B cells and granulocytes was performed. The analyses revealed a significant increase in neutrophils and decrease in eosinophils in granulocytes infected with A. veronii. Activation of neutrophils enhanced ribosome biogenesis by up-regulating the expression of rps12 and rpl12 to fight against invading pathogens. Crucial pro-inflammatory mediators il1b, ighv1-4, and the major histocompatibility class II genes mhc2a and mhc2dab, which are involved in virulence processes, were up-regulated, suggesting that A. veronii activates an immune response that presents antigens and activates immunoglobulin receptors in B cells. These cellular immune responses triggered by infection with A. veronii enriched the available scRNA-seq data for teleosts, and these results are important for understanding the evolution of cellular immune defense and functional differentiation of head kidney cells.
Project description:Grass carp is the most produced freshwater fish species in China. However, frequent outbreaks of bacterial diseases caused by Aeromonas ssp. have led to huge economic losses in grass carp farming. Various omics technologies have been used to study the response of grass carp to these pathogens. For instance, the transcriptional profile of the spleen from grass carp challenged with A. hydrophila, which revealed significant enrichment of gene clusters, including phagocytosis, complement system, cytokines, antigen processing and presentation, pattern recognition receptors, cell adhesion molecules, apoptosis, and antioxidant enzymes. Furthermore, a large number of differentially expressed genes related to inflammation were identified in the intestinal transcriptome of grass carp infected with A. hydrophila. However, the immune response of grass carp infected with A. veronii remains unresolved at the multi-omics level. In the present study, an intestinal infection model was established in grass carp using the isolated A. veronii strain EL07, and the differentially expressed genes and proteins in the intestinal and differentially expressed metabolites in serum were analyzed. The results may contribute to a better understanding of the pathogenesis of grass carp enteritis caused A. veronii.